Early Assessment of an Approach to Determining the Predictive Coverage of Case-Based Reasoning with Adaptation through CARMA

Abstract

CARMA is a decision-support system for managing grasshopper infestations which uses an approach called approximate-model-based adaptation whereby case-based reasoning (CBR) provides an approximate solution and model-based reasoning adapts this approximation into a precise solution. CARMA's predictive accuracy on a set of known cases confirmed the ability of the technique. The evaluation was not expanded beyond the initial set of known cases due to the human effort involved in constructing such cases. We provide an overview of CARMA, and detail initial attempts to establish a process for the automatic evaluation of such systems in order to identify potential gaps in predictive coverage using Monte Carlo methods. We propose that any generated situation which produces large adjustments in prediction during adaptation suggests a potential gap in the predictive ability of a CBR system. This represents an extension of prior CBR work which considers only the matching stage when evaluating predictive coverage.

Control of Pest Grasshoppers in North America

“…During outbreaks, vast infested territories were treated with a pesticide, which involves considerable monetary and environmental costs. During the 1986–1988 outbreaks, 4.1 L of insecticides were sprayed to cover 8.1 hectares of western rangeland with a program expenditure of $75 million [ 17 ]. Keeping grasshopper densities below economic thresholds is costly, and there is concern about the negative environmental effects of large-scale chemical control practices [ 18 ].…”

“…In 2003, the Dimilin RAATs method was applied in eastern Wyoming to protect 0.2 hectares from pest grasshopper species assemblages and has been shown to be very effective [ 17 , 24 ]. The RAATs method is best used with an insecticide that has sufficient residual effectiveness, allowing grasshoppers to move into the treated swaths from the untreated areas while it is still efficacious.…”

“…As an Insect Growth Regulator (IGR) which interferes with immature insect molts, Dimilin is currently the product of choice in both federal and private RAATs grasshopper control programs in the western United States. RAATs reduce the cost of application as well as the amount of insecticide needed, thus making control products more economically and environmentally viable [ 17 ]. In 2010, Dimilin RAATs were successfully applied to almost 2.4 hectares of Wyoming rangelands to control a severe grasshopper outbreak, with an average cost of only $1.25 per protected hectare [ 25 ].…”